It is known that syndiotactic polymethyl methacrylate (hereinafter, may be abbreviated to st-PMMA) forms a spiral structure when an organic solvent such as toluene or acetone is incorporated, and undergoes gelation or crystallization (see Non-Patent Documents 1 to 3). The crystal structure usually adopts a spiral conformation that is loosely wound at about 18/1, and the interior of the spiral has a space measuring about 1 nm in diameter, in which space solvent molecules are included.
The inventors of the present invention have already completed an invention relating to a fullerene-macromolecule complex in which fullerene is included inside the spiral conformation of a syndiotactic polymethacrylate-type or syndiotactic polyacrylate-type polymer, and a process for producing the same, and filed a patent application thereon (see Patent Document 1).
Examples reported hitherto to control the direction of spiral winding using a general-purpose polymer, are limited to polymethacrylate-type or polyacrylate-type isotactic polymers, and are also limited to macromolecules having a structure with bulky side chains. The direction of winding of a resulting spiral polymer was determined by the chiral initiator or auxiliary agent used in the polymerization reaction, and the polymer had a static spiral structure that could not be altered thereafter (Non-Patent Document 4).
As a methacrylic acid ester polymer having such a unidirectionally wound spiral structure, isotactic poly(triphenylmethyl methacrylate) is well known (for example, Non-Patent Document 5). This unidirectionally wound polymer has been put to practical use in columns for separation of chiral compounds. However, such a polymer has a disadvantage that the bulky tertiary ester group is prone to undergo hydrolysis and easily changes to carboxylic acid, and as a result, the spiral structure is readily destroyed (Non-Patent Document 6). Furthermore, since the raw material is a special ester called triphenylmethyl ester and is not a general-purpose monomer, there is another disadvantage that the synthesis processes are complicated, and the production cost goes up. This has been a significant problem in the practical use of the polymer.
Patent Document 1: Japanese Patent Application No. 2006-238368
Non-Patent Document 1: Kusuyama, H.; Takase, M.; Higashihata, Y.; Tseng, H.; Chatani, Y.; Tadokoro, H. Polymer, 1982, 23, 1256.
Non-Patent Document 2: Kusuyama, H.; Miyamoto, N.; Chatani, Y.; Tadokoro, H. Polymer 1983, 24, 119.
Non-Patent Document 3: Berghmans, M.; Thihs, S.; Cornette, M.; Berghmans, H.; Schryver, F. C. Macromolecules 1994, 27, 7669.
Non-Patent Document 4: Nakano, T.; Okamoto, Y. Chem. Rev. 2001, 101, 4013.
Non-Patent Document 5: Okamoto, Y.; Suzuki, K.; Ohta, K.; Hatada, K.; Yuki, H. J. Am. Chem. Soc. 1979, 101, 4763.
Non-Patent Document 6: Okamoto, Y.; Yashima, E.; Ishikura, M.; Hatada, K. Polym. J. 1987, 19, 1183.
Non-Patent Document 7: Spevacek, J.; Schneider, B. Adv. Colloid Interface Sci. 1987, 27, 81.
Non-Patent Document 8: Yoshida, Z.; Takekuma, H.; Takekuma, S.; Matsubara, Y. Angew. Chem. Int. Ed. Engl. 1994, 33, 1597.